This invention relates to sampling devices.
According to the present invention there is provided a sampling device comprising a closed reaction vessel, and a cylinder formed integrally with a wall of the vessel and having a bore in which a plunger is mounted for sliding sealing movement, the inner end of the bore being sealed from the interior of the vessel by a sealing element capable of being ruptured by the application of force against the sealing element by the plunger, part of the plunger projecting externally from the bore and having on its surface means for holding a predetermined quantity of a sample, and the arrangement being such that said part of the plunger carrying the sample can by depression of the plunger be moved into the interior of the vessel.
According to a preferred feature of the invention said means for holding a predetermined quantity of a sample comprises one or more holes or recesses in the plunger. In a preferred arrangement, said means for holding a predetermined quantity of a sample comprises a plurality of circumferential groves in the plunger, in which grooves a predetermined quantity of a sample can be retained by surface tension.
According to another preferred feature of the invention, the plunger is adapted to seal the bore when the said part is disposed in the interior of the vessel. For this purpose, the end portion of the plunger remote from the vessel may be of divergent cross-section, or may have one or more circumferential sealing ribs, so as to be capable of forming a tight seal in said bore when the said part of the plunger is disposed within the interior of the vessel.
According to a further preferred feature of the invention, the vessel has at least one chamber in the wall thereof which chamber is isolated from the interior of the vessel by a first seal and from the ambient surroundings by a second seal and which is intended to contain a reagent, and a second plunger mounted in a bore in a second cylinder on the wall of the chamber which plunger is operable to rupture said second and first seals in succession and serves then to seal the chamber (and in consequence the interior of the vessel) from the ambient surroundings.